Please make sure you have one of the following apps installed on your smartphone.
The authentication code will be updated at regular intervals (about 30 seconds) and when it's updated, the old verification code will not be available.
You will need to open the application (Google Authenticator, IIJ SmartKey etc) and enter the latest authentication code to authenticate.
Please wait for the authentication code to be updated before entering the code.
Depending on the authentication application, the code may blink in red to indicate that the code is about to change.
In order to use the authentication app properly, the time setting of devices (smartphone, tablet, etc) which the app runs must be correct.
If you are unable to authenticate even after entering the latest code, please make sure that your device's time setting is correct.
Two-step authentication using the app is basically depend on the device you set up.
Only the device that has set up the two-step authentication can check the authentication code and authenticate.
Therefore, in case you delete the authentication account, change the device model, delete or reinstall the app, the authentication information will be lost and you won't be able to authenticate.
If you can no longer check the authentication code, please contact us through the contact form.